Ball Valve High quality ball valve Industrial ball valve Ball Valve with best price Ball Valve with ISO,CE
Ball Valve
Ball Valve
High quality ball valve
Industrial ball valve
Ball Valve with best price
Ball Valve with ISO,CE
A ball valve is a valve with a spherical disc, the part of the valve which controls the flow through it.
The sphere has a hole, or port, through the middle so that when the port is in line with both ends
of the valve, flow will occur.
When the valve is closed, the hole is perpendicular to the ends of the valve, and flow is blocked.
The handle or lever will be inline with the port position letting you "see" the valve's position. The
ball valve, along with the butterfly valve and plug valve, are part of the family of quarter turn valves.
Ball valves are durable and usually work to achieve perfect shutoff even after years of disuse. They
are therefore an excellent choice for shutoff applications (and are often preferred to globe valves
and gate valves for this purpose).
They do not offer the fine control that may be necessary in throttling applications but are sometimes
used for this purpose.
Ball valves are used extensively in industrial applications because they are very versatile, supporting
pressures up to 1000 bars and temperatures up to 482°F (250°C). Sizes typically range from 0.2 to
11.81 inches (0.5 cm to 30 cm). They are easy to repair and operate.
The body of ball valves may be made of metal, plastic or metal with a ceramic center. The ball is often
chrome plated to make it more durable.
A ball-check valve is a type of check valve with a ball without a hole for a disc, and is not covered in
this article.
There are five general body styles of ball valves: single body, three piece body, split body, top entry,
and welded.
The difference is based on how the pieces of the valve—especially the casing that contains the ball
itself—are manufactured and assembled. The valve operation is the same in each case.
In addition, there are different styles related to the bore of the ball mechanism itself:
A full port or more commonly known full bore ball valve has an over-sized ball so that the hole in the
ball is the same size as the pipeline resulting in lower friction loss. Flow is unrestricted but the valve
is larger and more expensive so this is only used where free flow is required, for example in pipelines
which require pigging.
In reduced port or more commonly known reduced bore ball valves, flow through the valve is one
pipe size smaller than the valve's pipe size resulting in flow area being smaller than pipe. As the flow
discharge remains constant and is equal to area of flow (A) times velocity (V), the velocity increases
with reduced area of flow.
A V port ball valve has either a 'v' shaped ball or a 'v' shaped seat. This allows the orifice to be opened
and closed in a more controlled manner with a closer to linear flow characteristic. When the valve is in
the closed position and opening is commenced the small end of the 'v' is opened first allowing stable flow
control during this stage. This type of design requires a generally more robust construction due to higher
velocities of the fluids,which might damage a standard valve. These can be referred to as a type of control
valve but are not as accurate as a pressure regulator.
A Kompact ball valve is a "full port" valve that fits between 2 flanges. Due to its configuration, its body is
slimmer however and less metal.
Cavity filler Ball Valve. Many industries encounter problem with residues in the ball valve. Where the fluid
is meant for human consumption, residues may also be health hazard, and when where the fluid changes
from time to time contamination of one fluid with another may occur. Residues arise because in the half
open position of the ball valve a gap is created between the ball bore and the body in which fluid can be
trapped. To avoid the fluid getting into this cavity, the cavity has to be plugged, which can be done by
extending the seats in such a manner that it is always in contact with the ball. This type of ball valve is
known as Cavity Filler Ball Valve.
There are a few types of ball valves related to the attachment and lateral movement of the ball:
A trunnion ball valve has additional mechanical anchoring of the ball at the top and the bottom, suitable for
larger and higher pressure valves (say, above 10 cm and 40 bars).
A floating ball valve is one where the ball is not held in place by a trunnion. In normal operation, this will cause
the ball to float downstream slightly. This causes the seating mechanism to compress under the ball pressing
against it. Furthermore, in some types, in the event of some force causing the seat mechanism to dissipate
(such as extreme heat from fire outside the valve), the ball will float all the way to metal body which is designed
to seal against the ball providing a somewhat failsafe design.
Manually operated ball valves can be closed quickly and thus there is a danger of water hammer. Some ball
valves are equipped with an actuator that may be pneumatically or motor operated. These valves can be used
either for on/off or flow control. A pneumatic flow control valve is also equipped with a positioner which
transforms the control signal into actuator position and valve opening accordingly.
Three-way ball valves have an L- or T-shaped hole through the middle. The different combinations of flow are
shown in the figure. It is easy to see that a T valve can connect any pair of ports, or all three, together, but the
45 degree position which might disconnect all three leaves no margin for error. The L valve can connect the
center port to either side port, or disconnect all three, but it cannot connect the side ports together.
Multi-port ball valves with 4 ways, or more, are also commercially available, the inlet way often being orthogonal
to the plane of the outlets. For special applications, such as driving air-powered motors from forward to reverse,
the operation is performed by rotating a single lever four-way valve. The 4-way ball valve has two L-shaped ports
in the ball that do not interconnect, sometimes referred to as an "×" port.
Ball valves in sizes up to 2 inch generally come in single piece, two or three piece designs. One piece ball valves
are almost always reduced bore, are relatively inexpensive and generally are throw-away. Two piece ball valves
are generally slightly reduced (or standard) bore, they can be either throw-away or repairable. The 3 piece design
allows for the center part of the valve containing the ball, stem & seats to be easily removed from the pipeline.
This facilitates efficient cleaning of deposited sediments, replacement of seats and gland packings, polishing
out of small scratches on the ball, all this without removing the pipes from the valve body. The design concept
of a three piece valve is for it to be repairable.
Ball Valve
